Combination pilot burner and flame detector



Dec. 21, 1965 M. J. MCINERNEY ETAL 3,224,487

COMBINATION PILOT BURNER AND FLAME DETECTOR 2 Sheets-Sheet 1 Filed May 25, 1963 FIG.

INVENTORS MICHAEL J. MSINERNEY OSEPH CZY BY dn (Qi ATTORNEY Dec. 21, 1965 M. J. MCINERNEY ET AL 3,224,487

COMBINATION PILOT BURNER AND FLAME DETECTOR Filed May 25, 1963 2 Sheets-Sheet 2 INVENTORS MICHAEL J. MQINERNEY JOSEPH l CZYL BYDMAM i4@ ATTORNEY United States Patent O 3,224,487 COMBINATION PILOT BURNER AND FLAME DETECTR Michael J. Mclnerney, Highland Park, and Joseph L. Czyl, Harvey, lll., assignors to Vapor Corporation, Chicago, Ill., a corporation of Delaware Filed May 23, 1963, Ser. No. 282,641 2 Claims. (Cl. 158-28) This invention relates in general to a heating plant, and more particularly to a combination pilot burner and llame detector mounting assembly for use in a heating plant, such as a steam generator, a hot oil heater, a hot water heater, and the like, although other uses and purposes may be appreciated from the following description by those skilled in the art.

The combination pilot burner and flame detector mounting assembly of the present invention essentially defines a single unit capable of providing a pilot flame for the main burner in a heating plant and for providing means for detecting llame in the pilot burner and llame in the main burner to thereby safely control the operation of the pilot and main burners. Heretofore, the pilot burner and llame detector were separate units which necessitated critical adjustment of the flame detector to effectuate its proper operation and to detect both the flame of the pilot burner and of the main burner. The present invention obviates this d-ifllculty by uniquely combining the pilot `burner with the llame detector.

In the present invention, the pilot burner comprises an elongated tube having fuel fed thereto and being adjusted so that the flame will ignite the main burner. A flame detection unit o-f the usual type having a sighting tube or pipe is employed wherein the sighting tube or pipe extends through the center area of the pilot burner tube or nozzle. An electrical ignitor such as a spark plug is employed for igniting the pilot burner. In starting a heating plant equipped with the present invention, fuel is delivered to the pilot burner nozzle and simultaneously therewith the spark plug is energized to ignite the pilot flame. After a llame proving period is established of a predetermined time, and the llame detector has detected the pilot flame, a signal is given to a burner valve to deliver fuel to the main burner. Again after a llame proving period is established with the main burner, the pilot burner is turned off, and thereafter the llame detector of the combination pilot burner and flame detector assembly operates to detect the burner flame. If the llame detector ldetermines that the burner llame is n-ot established or not properly established, a signal may be transmitted to close the main burner fuel valve and shut down the heating plant.

Accordingly, it is an object of the present invention to provide a combination pilot burner and flame detector mounting assembly that is capable of combining the pilot burner, ignitor and flame detector into a single unit.

Another object of this invention resides in the provision of a combination pilot and llame detector mounting assembly that places the llame detector line olf sight within the pilot flame enevelope.

Another object of this invention is to provide a combination pilot burner and flame detector, wherein the llame detector includes a sighting tube arranged within the nozzle of the pilot burner so that by controlling the length of the sighting tube, the pilot llame is forced to be of sulcient size to accomplish ignition.

A further object of this invention is in the provision of a combination pilot burner and llame detector, wherein a spark plug is provided for ignition of the pilot burner, and the llame detector includes a sighting tube, the control by length of which prevents unwanted ultraviolet detection of the spark generated by the spark plug.

ICS

Still another object of this invention is to provide a combination pilot burner and flame detector unit that may be aimed through the fire pot of a stream generator for optimum main flame detection without regard to pilot position, since the pilot is always in the same location relative to the detector.

Other objects, features and advantages of the invention will be apparent .from the yfollowing detailed disclosure, taken in conjunction with the accompanying sheets of drawings, wherein like reference numerals refer to like parts, in which:

FIG. l is a diagramm-atic view of a fragmentary fire pot of a heating plant showing the use of the present invention in connection with a main burner;

FIG. Z is an enlarged longitudinal sectional view taken through a main burner and a combination pilot burner and flame detector according to the invention; and

FIG. 3 is an enlarged longitudinal sectional view taken through a main burner and a modified combination pilot burner and flame detector according to the present invention.

Referring to the drawings and particularly to FIG. l, a fire pot of a heating plant is generally designated by the numeral 10 and has mounted thereon a main burner 11 and a combination pilot burner and llame detector 12 according to the present invention. The combination pilot burner and lflame detector 12 includes generally a pilot burner 13, a flame detector 14, and a spark plug or equivalent ignitor 15. A motor or solenoid actuated valve 16 controls the opening and closing of the fuel line 17 to the pilot burner 13, while a motor or solenoid actuated valve 1S controls the opening and closing of the fuel line 19 to the main burner 11.

In general the operation of the pilot burner and flame detector is associated with the starting of the heating plant and with c-ontinued detection of the flame from the main burner. Electrical circuitry including relays or their equivalents (not shown) will be employed to coordinate the `operation of the combination pilot burner and llame detector, and the main burner. T o start the heating plant, a switch is operated to substantially simultaneously open the fuel valve 16 in the pilot line 17 and energize the electrical ignitor or spark plug 15. A flame proving period is allowed, and if the flame detector 14 detects a flame in the pilot burner 13, a signal is transmitted to the electrical circuitry to operate the main burner valve 18 and lopen the fuel line 19 to the main burner 11. The fuel discharged from the main burner 11 is then ignited by the llame of the pilot burner 13. Following a flame proving period of the main burner, the spark plug 15 is deenergized and the pilot burner fuel valve 16 is closed to shut down the pilot burner 13. The flame detector then holds in on the tlame of the main burner 11. Should the llame detector not respond to any llame energy, that is, not detect any llame in the main burner, a signal will be transmitted to the electrical circuitry to close the main burner fuel valve 18. Similarly, in starting of the pilot burner, if the flame detector 14 does not detect a flame in the pilot burner 13 after a re proving period, the detector will cause the pilot burner valve 16 to close and cause the spark plug 15 to be deenergized, without further affecting the 'opening of the main burner valve 18.

The flame detector 14 includes generally a ilame energy responsive unit 20 and a sighting tube Ior pipe 21. The sighting tube or pipe 21 is mounted within the pilot burner housing as seen in FIG. 1 so that the flame detector line of sight is placed within the flame envelope of the pilot burner 13. Accordingly, the combination pilot burner and flame detector must be `oriented so that the pilot flame is capable of effecting proper ignition of the main burner. Further, the unit may additionally be oriented so 'that the sighting tube 21 is aimed through the fire pot for optimum main ame detection without regard to pilot flame position, since the pilot flame is always in the same location relative to the llame detector.

Referring now -to the specific embodiment of FIG. 2, a more detailed construction of the combination pilot burner and llame detector, and main burner is shown, wherein the main burner is designated by the numeral 11A, while the combination pilot burner and flame detector is designated by the numeral 12A.

Any suitable Itype of main burner may be employed, such as the burner 11A shown in FIG. 2 that may be gas, oil, or gas and -oil fired. This burner includes a fuel nozzle 22 projecting through and mounted on the wall of the lire pot 10. A fuel inlet tting 23 is adapted to be connected to a fuel line such as the line 19, FIG. 1. In each instance, lthe fuel line would be controlled by the flame detector 14.

The combination pilot burner and flame detector 12A, also mounted on the wall of the re pot 10, includes a gas nozzle 26 comprising an elongated tubular member projecting through the wall of the tire pot and terminating within the lire pot With an angularly cut-off end, although the end may be straight. It is this elongated tubular member that is supported by a bracket 27 carried on the wall of the re pot 10. A gas line fitting 28 is mounted to 'extend laterally of the tubular body youtside of the fire pot and is adapted to be connected to a gas fuel line such as the line 17 in FIG. 1. A spark plug 29 is provided to ignite the gas flowing from the nozzle 26.

The flame detecting unit may be of any desired type, and in this embodiment includes a scanner or flame responsive unit 30 mounted on a heat block 31 that is in turn mounted on a seal-off assembly 32. The scanner, heat block and seal-off assembly are axially aligned and carried on a stabilizer assembly 33 that has secured thereto the elongated tubular member of the gas nozzle 26. The heat block 31 is made of synthetic material to insulate the scanner 30 from the heat conducted by the gas nozzle tubular member, while the seal-off assembly contains a glass window 32a which prevents hot gases from reaching the scanner 30. The heat block and seal-off assembly are hollow to permit the scanner to respond to flame energies traveling through same. Similarly, a bore is provided through the adapter assembly 33 to continue the sight line toward the flame. A sighting tube lor pipe 34 is mounted within the tubular member of the gas nozzle 26 and communicates at one end with the bore in the adapter assembly 33 while opening at the other end at the base of the pilot flame and in substantial alignment with the end of the nozzle 26. The sighting tube may be increased or decreased in length to control the sighting action. By controlling the length of the sighting tube, the pilot flame is forced to be of suicient size to accomplish ignition of the main burner.

One satisfactory scanner mechanism comprises a lead sulphide photocell of the type disclosed in the instruction sheet published by Minneapolis-Honeywell Regulator Company and bearing the number 95-2123. Also the details of the heat block 31 and the seal-off assembly 32 are disclosed in this instruction sheet.

Referring now to the embodiment of FIG. 3, it will be seen that a similar type of fuel burner 11A is employed, while a modified combination pilot burner and llame detector 12B is shown. The combination pilot burner and flame detector 12B includes an adapter assembly 34 having an axial bore extending therethrough and receiving at one end a sighting tube or pipe 35. Concentrically mounted with the sighting tube is a tubular fuel nozzle 36 that is mounted on a bracket 37 and secured to the wall of the lire pot 10. Therefore, the sighting tube 35 extends within the nozzle 36 and in the embodiment shown extends to the end of the nozzle. Both the nozzle and the sighting tube terminate in a plane perpendicular to the axes of the sighting tube and nozzle. A gas inlet 38 is mounted on the nozzle 36 outside of the fire pot 10 and adapted to be connected to a gas line. Further, an air inlet 39 is mounted on the gas nozzle 36 for purposes of being connected to a source of air which is fed into the gas nozzle to aid the combustion of the gas and to cool the sighting tube 35. A spark plug (not shown) is also provided for igniting the pilot burner 12B.

An elongated tubular casing 40 extends from the end of the adapter assembly 34 opposite the gas nozzle 36 and serves as a heat block and to have mounted therein a window 41 of quartz or suitable material for preventing the hot gases from reaching the scanner that is mounted on the end of the casing 40 and designated by the numeral 42. To additionally provide cooling for the casing 40, an air inlet 43 may be mounted on the casing and adapted to be connected to a supply of cooling air. A hole or aperture 44 is also provided in the casing to permit exhausting of the cooling air. While the scanner 42 may take the same form as the scanner 30 in FIG. 2, it is preferred that it be of the type that is capable of sensing the ultraviolet radiation of the gas, oil or combination gas-oil flames. A suitable type of detector for this purpose may be the model C7012E Ultra-Vision llame detector of Minneapolis-Honeywell Regulator Company and as set forth in their instruction sheet form number -5468.

From the foregoing, it should be appreciated that the present invention will improve ignition and flame detector performance in a heating plant or the like by providing the combination pilot flame burner and flame detector which is capable of optimum main llame detection without regard to the pilot burner position.

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention, but it is understood that this application is to be limited only by the scope of the appended claims.

The invention is hereby claimed as follows:

1. In combination with a re pot for a heating plant, a main burner extending into the tire pot, a combination pilot burner and flame detector for detecting the pilot and main burner flames extending into the fire pot and at an inclined angle to the axis of and within heat proximity to said main burner, said pilot burner and flame detector comprising, an elongated tubular member projecting into the re pot, said tubular member being open at the end extending within the lire pot to define at said open end a fuel nozzle and being closed at the end extending outside of the fire pot, a fuel inlet on said tubular member located at the closed end outside of the fire pot, a sighting tube extending through the closed end of said tubular member and centrally therethrough terminating at a point substantially coincident with the open end of said tubular member and defining with said tubular member an annular in cross-section fuel passageway extending from the closed end of said tubular member to the open end thereof, and a flame detection unit mounted on said tube outside of said tubular member for detecting the ame at the nozzle, the inclination of said combination pilot burner and flame detector to said main burner being such that said detector responds to the main burner flame.

2. The combination as defined in claim 1, and an air inlet on said tubular member at the closed end thereof for introducing air into said fuel passageway.

References Cited by the Examiner UNITED STATES PATENTS 2,295,045 9/ 1942 Mettler 158-28 2,592,847 4/1952 Babies 158-28 2,627,308 2/1953 Clark 158-28 2,721,607 10/1955 Damon et al. 158--28 2,905,236 9/1959 Wright 158-28 2,963,353 12/1960 Eastman 158-28 JAMES W. WESTHAVER, Primary Examiner. 

1. IN COMBINATION WITH A FIRE POT FOR A HEATING PLANT, A MAIN BURNER EXTENDING INTO THE FIRE POT, A COMBINATION PILOT BURNER AND FLAME DETECTOR FOR DETECTING THE PILOT AND MAIN BURNER FLAMES EXTENDING INTO THE FIRE POT AND AT AN INCLINED ANGLE TO THE AXIS OF AND WITHIN HEAT PROXIMITY TO SAID MAIN BURNER, SAID PILOT BURNER AND FLAME DETECTOR COMPRISING, AN ELONGATED TUBULAR MEMBER PROJECTING INTO THE FIRE POT, SAID TUBULAR MEMBER BEING OPEN AT THE END EXTENDING WITHIN THE FIRE POT TO DEFINE AT SAID OPEN END A FUEL NOZZLE AND BEING CLOSED AT THE END EXTENDING OUTSIDE OF THE FIRE POT, A FUEL INLET ON SAID TUBULAR MEMBER LOCATED AT THE CLOSED END OUTSIDE OF THE FIRE POT, A SIGNTING TUBE EXTENDING THROUGH THE CLOSED END OF SAID TUBULAR MEMBER AND CENTRALLY THERETHROUGH TERMINATING AT A POINT SUBSTANTIALLY COINCIDENT WITH THE OPEN END OF SAID TUBULAR MEMBER AND DEFINING WITH SAID TUBULAR MEMBER AN ANNULAR IN CROSS-SECTION FUEL PASSAGEWAY EXTENDING FROM THE CLOSED END OF SAID TUBULAR MEMBER TO THE OPEN END THEREOF, AND A FLAME DETECTION UNIT MOUNTED ON SAID TUBE OUTSIDE OF SAID TUBULAR MEMBER FOR DETECTING THE FLAME AT THE NOZZLE, THE INCLINATION OF SAID COMBINATION PILOT BURNER AND FLAME DETECTOR TO SAID MAIN BURNER BEING SUCH THAT SAID DETECTOR RESPONDS TO THE MAIN BURNER FLAME. 